Fix DsMapDynamicReturnTypeExtension

src/Type/Php/DsMapDynamicReturnTypeExtension.php

@@ -8,6 +8,7 @@
 use PHPStan\Reflection\ParametersAcceptorSelector;
 use PHPStan\Type\DynamicMethodReturnTypeExtension;
 use PHPStan\Type\Generic\TemplateType;
+use PHPStan\Type\Generic\TemplateTypeScope;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
 use PHPStan\Type\UnionType;
@@ -27,22 +28,33 @@ public function isMethodSupported(MethodReflection $methodReflection): bool
 
 	public function getTypeFromMethodCall(MethodReflection $methodReflection, MethodCall $methodCall, Scope $scope): Type
 	{
-		$returnType = $methodReflection->getVariants()[0]->getReturnType();
+		$returnType = ParametersAcceptorSelector::selectFromArgs(
+			$scope,
+			$methodCall->args,
+			$methodReflection->getVariants()
+		)->getReturnType();
 
 		if (count($methodCall->args) > 1) {
-			return ParametersAcceptorSelector::selectFromArgs(
-				$scope,
-				$methodCall->args,
-				$methodReflection->getVariants()
-			)->getReturnType();
+			return $returnType;
 		}
 
 		if ($returnType instanceof UnionType) {
 			$types = array_values(
 				array_filter(
 					$returnType->getTypes(),
 					static function (Type $type): bool {
-						return !$type instanceof TemplateType;
+						if (
+							$type instanceof TemplateType
+							&& $type->getName() === 'TDefault'
+							&& (
+								$type->getScope()->equals(TemplateTypeScope::createWithMethod('Ds\Map', 'get'))
+								|| $type->getScope()->equals(TemplateTypeScope::createWithMethod('Ds\Map', 'remove'))
+							)
+						) {
+							return false;
+						}
+
+						return true;
 					}
 				)
 			);
@@ -51,6 +63,10 @@ static function (Type $type): bool {
 				return $types[0];
 			}
 
+			if (count($types) === 0) {
+				return $returnType;
+			}
+
 			return TypeCombinator::union(...$types);
 		}
 

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -5695,6 +5695,11 @@ public function dataBug4707(): array
 		return $this->gatherAssertTypes(__DIR__ . '/data/bug-4707.php');
 	}
 
+	public function dataBug4545(): array
+	{
+		return $this->gatherAssertTypes(__DIR__ . '/data/bug-4545.php');
+	}
+
 	/**
 	 * @dataProvider dataArrayFunctions
 	 * @param string $description
@@ -11317,6 +11322,7 @@ private function gatherAssertTypes(string $file): array
 	 * @dataProvider dataBug4213
 	 * @dataProvider dataBug4657
 	 * @dataProvider dataBug4707
+	 * @dataProvider dataBug4545
 	 * @param string $assertType
 	 * @param string $file
 	 * @param mixed ...$args

tests/PHPStan/Analyser/data/bug-4545.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace Bug4545;
+
+use Closure;
+use Ds\Hashable;
+use Ds\Map;
+use Ds\Set;
+use function PHPStan\Analyser\assertType;
+
+class Foo
+{
+
+	/**
+	 * Returns keys which either exist only in one of the maps or exist in both but their associated values are not equal.
+	 *
+	 * @template TKey of Hashable
+	 * @template TValue1
+	 * @template TValue2
+	 *
+	 * @param Map<TKey, TValue1> $firstMap
+	 * @param Map<TKey, TValue2> $secondMap
+	 * @param Closure(TValue1, TValue2): bool $comparator
+	 *
+	 * @return Set<TKey>
+	 */
+	function compareMaps(Map $firstMap, Map $secondMap, Closure $comparator): Set
+	{
+		$firstMapKeys = $firstMap->keys();
+		$secondMapKeys = $secondMap->keys();
+		$keys = $firstMapKeys->xor($secondMapKeys);
+		$intersect = $firstMapKeys->intersect($secondMapKeys);
+		foreach ($intersect as $key) {
+			assertType('TValue1 (method Bug4545\Foo::compareMaps(), argument)', $firstMap->get($key));
+			assertType('TValue2 (method Bug4545\Foo::compareMaps(), argument)', $secondMap->get($key));
+			assertType('int|TValue2 (method Bug4545\Foo::compareMaps(), argument)', $secondMap->get($key, 1));
+		}
+
+		return $keys;
+	}
+
+}
+